The present invention relates to a method for renewing or repairing a refractory plate employed as a stationary bottom plate or as an adjustably movable plate in a sliding closure unit for controlling the discharge of molten metal from a metallurgical vessel, the refractory plate having a planar sealing surface with a sealing area at a first portion of the plate and a discharge opening extending through the plate at a second area thereof, whereby during use of the sliding closure unit the plate becomes damaged and eroded in the discharge opening, and particularly at a wear area around the discharge opening at the sealing surface.
It is commonly known in the art to renew, maintain or repair such refractory plates which prematurely wear out at the discharge opening or openings as a result of the formation of cracks due to thermal stresses, corrosive and erosive attacks by the discharged stream of molten metal, as well as frictional forces between the stationary bottom plate and the adjustably movable plate, such renewal or repair lowering the cost of replacement of worn plates during operation. Thus, instead of new plates, there are employed repaired plates wherein, in principle, the wear area around the discharge opening has been leveled by machining, and the plate material thus lost is replaced with prefabricated inserts or with a filler material. Thus, West German Patent No. 32 43 305 proposes production steps according to which an eroded teeming hole is reamed coaxially almost to the peripheral edge of the plate, and the widened hole is filled with a refractory pourable material, while the flow section of the discharge opening is maintained or kept clear by employing, if necessary, a prefabricated ring which defines the discharge opening in the sliding surface of the plate. In this case, the corrective repair or maintenance is limited only to the discharge opening in the plate, and no attention is paid to the sealing surface of the plate.